Device and method for testing the burning rate of an initiating agent for a carbon dioxide fracturing device under high pressure

Abstract

The application provides a testing device and method for the burning rate of an excitation agent for a carbon dioxide fracturing device under high pressure, which comprises a high-pressure-resistant visual module, a constant-pressure valve, a pressure gauge, an ignition assembly and a high-temperature-resistant transparent quartz charging pipe; the high-pressure-resistant visual module is internally provided with a cavity, a base at the bottom and a pipe opening at the top, and is provided with a bursting disc safety valve and a pressure ring at the pipe opening; the high-temperature-resistant transparent quartz charging pipe is installed in the cavity, and a plurality of mark groups are arranged on the high-temperature-resistant transparent quartz charging pipe; the ignition assembly is connected with the bursting disc safety valve and the high-temperature-resistant transparent quartz charging pipe; the bursting disc safety valve is provided with a liquid injection valve; the constant-pressure valve and the pressure gauge are both installed on the visual module, and the constant-pressure valve and the pressure gauge are electrically connected. The application can test the burning rate of the excitation agent for the carbon dioxide fracturing device in liquid carbon dioxide under different pressures, output the relationship between the burning rate of the excitation agent and the pressure, and master the burning rate law of the excitation agent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of CO2 phase change, in particular to a testing device and method for the burning speed of an excitation agent for a carbon dioxide fracturing device under high pressure. BACKGROUND

[0002] With the call for green and environmentally friendly construction of a beautiful home, liquid carbon dioxide phase change blasting technology with no destructive vibration and small dust ratio has been widely used in large-scale ore mining, rapid and safe blasting, rock fracturing, and tank wall dredging. With the large-scale popularization and application of liquid carbon dioxide phase change blasting technology, the requirements for the work efficiency and precise control of the technology are becoming higher and higher.

[0003] The main principle of liquid carbon dioxide phase change fracturing technology is that after the controller is powered on, the ignition head in the excitation agent in the liquid storage pipe is electrically ignited, igniting the excitation agent. The agent burns and releases heat and transfers heat to liquid carbon dioxide, causing it to change into supercritical carbon dioxide. When the pressure in the phase change pipe reaches the breaking strength of the bursting disc, the bursting disc breaks, and the high-pressure supercritical carbon dioxide instantaneously changes into gaseous carbon dioxide and rushes out of the liquid storage pipe. The volume of gaseous carbon dioxide is 500-600 times that of the same mass of liquid carbon dioxide. The volume of carbon dioxide instantaneously expands nearly 600 times. The high pressure generated during the continuous expansion of carbon dioxide gas spreads at a very high speed, thereby damaging the surrounding medium.

[0004] It can be seen that the excitation agent is the initial energy source for the work of liquid carbon dioxide phase change blasting technology. The burning speed of the excitation agent directly determines the speed of the pressure build-up in the liquid storage pipe, thereby affecting the time of the bursting disc opening. For a single carbon dioxide fracturing device, if the agent has not burned completely when the bursting disc opens, the work capacity will decrease. For large-scale multiple carbon dioxide fracturing devices, the speed of the bursting disc opening will affect the timing control of the blasting excitation. If the two are not matched, the blasting effect will be greatly reduced, affecting the yield. Therefore, the burning speed of the excitation agent must be accurately mastered to master its influence on the pressure build-up time of the liquid storage pipe and the adjustment of the bursting disc thickness, thereby effectively improving the work efficiency and achieving precise control of the timing of large-scale carbon dioxide blasting.

[0005] The performance of the excitation agent is similar to black powder, and different combustion speeds are shown under different pressure environments, and the combustion speed increases exponentially with the increase of pressure. Generally, the combustion speed-pressure curve is obtained by using a closed bomb for testing. However, when the excitation agent burns in liquid carbon dioxide, the heat generated will be absorbed by the liquid carbon dioxide, thereby affecting the combustion speed, and the combustion speed-pressure relationship presented is inconsistent with the combustion speed measured by the closed bomb, which is difficult to be directly applied to engineering guidance. In the closed bomb, liquid carbon dioxide is directly filled, and the heat absorption of carbon dioxide will instantaneously generate a pressure of hundreds of megapascals, so that the closed bomb will explode unless the wall thickness is increased, otherwise the explosion accident will occur. If the wall thickness of the closed bomb is increased, the closed bomb will be very heavy and lose its convenience.

[0006] Therefore, it is necessary to provide a test device for testing the combustion speed of the excitation agent for the carbon dioxide fracturing device under high pressure, which is efficient, convenient and safe. SUMMARY

[0007] In view of the above technical problems, the present application provides a test device and method for testing the combustion speed of the excitation agent for the carbon dioxide fracturing device under pressure, which can test the combustion speed of the excitation agent for the carbon dioxide fracturing device in liquid carbon dioxide under different pressures. By fitting the combustion speed data of the excitation agent under different pressures obtained by testing, the relationship between the combustion speed of the excitation agent and the pressure can be obtained, which provides guidance for better application of the carbon dioxide fracturing device in the blasting field.

[0008] The technical scheme of the present application is: a test device for testing the combustion speed of the excitation agent for the carbon dioxide fracturing device under high pressure, comprising a high-pressure-resistant visual module, characterized in that it further comprises a constant-pressure valve, a pressure gauge, an ignition assembly and a high-temperature-resistant transparent quartz charging pipe.

[0009] The high-pressure-resistant visual module is provided with a cavity for storing liquid carbon dioxide, the bottom of the high-pressure-resistant visual module is provided with a base, and the top is provided with a pipe opening communicating with the cavity, a bursting disc safety valve is arranged at the pipe opening, and a pressure ring is arranged on the top of the bursting disc safety valve; an observation window is arranged on the axial wall surface of the visual module, the charging pipe is installed in the cavity, and a plurality of mark groups are arranged on the side of the charging pipe facing the observation window; the ignition assembly is connected with the bursting disc safety valve and the high-temperature-resistant transparent quartz charging pipe; the bursting disc safety valve is provided with a liquid injection valve for injecting liquid carbon dioxide into the cavity;

[0010] The constant-pressure valve and the pressure gauge are installed on the visual module and communicate with the cavity, and the constant-pressure valve and the pressure gauge are electrically connected.

[0011] Preferably, the top of the bursting disc safety valve is provided with a cross-shaped notch which can be broken when the pressure is too high.

[0012] Preferably, the visual module further comprises a container, a first sealing ring, a second sealing ring and a cover, the container comprises a tube body, the bottom of the tube body is provided with the base, the top of the tube body is provided with the tube mouth, and the cavity is located in the inside of the tube body; the tube body is provided with a window for installing the observation window, the second sealing ring is arranged between the observation window and the window, and the observation window and the window are fixed by the cover; the tube body is provided with a mounting ring groove for mounting the first sealing ring, and the bursting disc safety valve is arranged on the first sealing ring.

[0013] Preferably, the inner bottom surface of the tube body is provided with a clamping seat, and the high-temperature-resistant transparent quartz charging tube is fixed in the clamping seat in a shaft hole clamping manner.

[0014] Preferably, the window is formed with a mounting table by sinking, and the observation window is embedded on the mounting table.

[0015] Preferably, the mounting recess is formed by sinking inward from the mounting table, and the second sealing ring is arranged on the mounting recess.

[0016] Preferably, the test device for the burning speed of the excitation agent of the high-pressure carbon dioxide fracturing device further comprises a gas release valve, and the gas release valve is installed on the high-pressure-resistant visual module and communicates with the inside of the cavity.

[0017] Preferably, the interval of the plurality of marking groups forms a time value.

[0018] The application also provides a method for testing by using the test device for the burning speed of the excitation agent of the high-pressure carbon dioxide fracturing device, comprising:

[0019] 1) setting the pressure value A of the liquid carbon dioxide in the high-pressure-resistant visual module for the constant pressure valve;

[0020] 2) filling the liquid carbon dioxide into the high-pressure-resistant visual module through the liquid injection valve to make the internal pressure reach the set value;

[0021] 3) setting up the camera and aiming at the charging tube at the position of the observation window, and starting the camera to complete the debugging;

[0022] 4) igniting the ignition assembly, the ignition assembly ignites and excites the agent in the charging tube, the excitation agent instantaneously transmits heat to the liquid carbon dioxide, the pressure in the high-pressure-resistant visual module instantaneously rises above the set value, and the constant pressure valve starts to work to keep the pressure in the high-pressure-resistant visual module within the set value range;

[0023] 5) calculation and analysis: when the excitation agent is ignited by the ignition assembly and burns, the burning surface in the charging tube transmits from top to bottom, sequentially passes through a plurality of marking groups to form a time parameter, and the burning speed of the excitation agent at the preset pressure value A is output according to the time parameter;

[0024] 6) open the gas exhaust valve to empty the gas in the visual module, take out and replace the charging tube;

[0025] 7) set the pressure value B of the liquid carbon dioxide in the visual module;

[0026] Repeat steps 2) to 6), and output the burning rate of the initiating agent at the preset pressure value B;

[0027] Repeat steps 1) to 6) until n preset pressure values of the burning rate of the initiating agent are outputted;

[0028] 8) perform data fitting on the obtained pressure and corresponding burning rate under n working conditions to obtain a relationship between the burning rate of the initiating agent for the carbon dioxide fracturing device and the confining pressure.

[0029] Preferably, in step 5), the interval between each two of the plurality of mark groups is set as a, and the plurality of mark groups form time t1-tm in sequence from top to bottom; the time before the pressure in the visual module is opened is set as t; the values of t1-tm and t are compared respectively, and the value greater than t is selected; then a is divided by the selected value greater than t, and thus the burning rate of the initiating agent is obtained.

[0030] Compared with the related art, the present application has the following beneficial effects:

[0031] I. The testing device for the burning rate of the initiating agent for the carbon dioxide fracturing device under high pressure can test the burning rate of the initiating agent for the carbon dioxide fracturing device in liquid carbon dioxide under different pressures;

[0032] II. By fitting the data of the burning rate of the initiating agent under different pressures obtained by testing, the relationship between the burning rate of the initiating agent and the pressure can be obtained, which provides guidance for better application of the carbon dioxide fracturing device in the blasting field.

[0033] Of course, it is not necessary for any product implementing the present application to achieve all the advantages described above at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The front view structural schematic diagram of the testing device for the burning rate of the initiating agent for the carbon dioxide fracturing device under high pressure provided by the present application;

[0035] Figure 2 is a side view schematic diagram; Figure 1

[0036] Figure 3 is an exploded structural schematic diagram of the visual module;

[0037] Figure 4 is a top view schematic diagram of the visual module; ​

[0038] Figure 5 is a schematic view of the internal section of the visual module;

[0039] Figure 6 is a schematic view of the structure of the container in Figure 3 ;

[0040] Figure 7 is a schematic view of the structure of the container in Figure 3 ;

[0041] Figure 8 is a schematic view of the structure of the safety valve in Figure 3 ;

[0042] Figure 9 is a schematic view of the structure of the safety valve in Figure 3 ;

[0043] Figure 10 is a schematic view of the structure of the charging tube in Figure 1 ;

[0044] Figure 11 is a schematic view of the structure of the ignition assembly in Figure 1 . DETAILED DESCRIPTION

[0045] The present application will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words “up”, “down”, “left”, “right” appear in the following text, they only mean the same direction as the up, down, left and right of the drawings, and do not limit the structure.

[0046] As shown in Figure 1 , Figure 2 , the test device for the burning speed of the excitation agent for the carbon dioxide fracturing device under high pressure provided by the embodiment includes a high-pressure-resistant visual module 1 (hereinafter referred to as the visual module), a high-temperature-resistant transparent quartz charging tube 2 (hereinafter referred to as the charging tube), a constant pressure valve 3, a gas release valve 5, a pressure gauge 6, a control power supply 7, a power supply wire 8, a signal wire 10, a pressure sensor 11 and an ignition assembly 12.

[0047] The visual module 1 is provided with a cavity for storing liquid carbon dioxide, and the charging tube 2 containing the excitation agent is placed in the cavity, and the burning speed of the excitation agent in the liquid carbon dioxide under a fixed pressure is calculated by combining the use of high-speed photography observation.

[0048] As shown in Figure 3 , Figure 4As shown, the visual module 1 comprises a container 1-1, a first sealing ring 1-2, a rupture disc safety valve 1-3 (hereinafter referred to as safety valve), a compression ring 1-4, a second sealing ring 1-5, a fastener 1-7 and a gland 1-8. As shown Figure 6 As shown, the container 1-1 comprises a tube body 1-1-1, and the cavity is arranged in the tube body 1-1-1. As shown Figure 6 、 Figure 7 As shown, a window is arranged on the tube body 1-1-1 in the axial direction, and the window is sequentially provided with a mounting platform 1-1-4 and a mounting groove 1-1-5 from the outside to the inside. The mounting platform 1-1-4 and the mounting groove 1-1-5 are both long rectangles adapted to the window. A plurality of mounting screw holes 1-1-6 are arranged between the mounting platform 1-1-4 and the mounting groove 1-1-5. As shown Figure 4 The part of the container 1-1 where the window is arranged protrudes outward from the container 1-1, protrudes in the radial direction of the container 1-1, and forms a flat surface at the outer end of the protrusion, which is beneficial for the installation of the observation window 1-6.

[0049] The bottom of the tube body 1-1-1 is provided with a base 1-1-10, and the top is provided with a tube opening communicating with the cavity. The diameter of the base 1-1-10 is larger than that of the tube body 1-1-1, which serves as a support. The tube body 1-1-1 is provided with a first interface 1-1-2 for mounting a constant pressure valve 3. In this embodiment, as shown Figure 1 The number of the constant pressure valve 3 is two, and the number of the first interface 1-1-2 corresponds to two.

[0050] As shown Figure 1 、 Figure 6 The tube body 1-1-1 is provided with a second interface 1-1-7 for mounting a pressure gauge 6, a third interface 1-1-8 for mounting a gas release valve 5, and a fourth interface 1-1-9 for mounting a pressure sensor 11.

[0051] As shown Figure 1 、 Figure 3 、 Figure 6 、 Figure 7 The second sealing ring 1-5 is installed in the mounting groove 1-1-5, and then the observation window 1-6 is arranged outside the second sealing ring 1-5 and is clamped in the mounting groove 1-1-5, and the protruding outer edge of the mounting groove 1-1-5 abuts against the edge of the observation window 1-6. Then the gland 1-8 is placed on the mounting platform 1-1-4 and covers the observation window 1-6, and the protruding outer edge of the mounting platform 1-1-4 abuts against the edge of the gland 1-8. Finally, the fastener 1-7 is screwed through the through hole on the gland 1-8 and the mounting screw hole 1-1-6. The observation window 1-6 is a high-pressure-resistant sapphire observation window.

[0052] AsFigure 5 、 Figure 7 As shown in the figure, the pipe body 1-1-1 is provided with a mounting ring groove 1-1-11 near the pipe opening, the first sealing ring 1-2 is arranged in the mounting ring groove 1-1-11, and the safety valve 1-3 is arranged on the first sealing ring 1-2. The safety valve 1-3 and the cavity are sealed by the first sealing ring 1-2. The upper end cover of the safety valve 1-3 is provided with a pressing ring 1-4.

[0053] As shown in the figure, Figure 5 The inner bottom surface of the pipe body 1-1-1 is provided with a clamping seat 1-1-12, and the clamping seat 1-1-12 is internally provided with a clamping hole matched with the charging pipe 2. The charging pipe 2 is fixed in the clamping hole of the clamping seat 1-1-12 in a shaft hole clamping manner. The clamping seat 1-1-12 protrudes upward by a distance to form an effective fixing wall surface for mounting the charging pipe 2, so as to ensure that the charging pipe 2 is in a straight state.

[0054] As shown in the figure, Figure 8 、 Figure 9 The safety valve 1-3 is provided with a first connecting post 1-3-1, a second connecting post 1-3-2, a liquid injection valve 1-3-3 and a cross-shaped notch 1-3-4. The cross-shaped notch 1-3-4 is arranged in the middle of the safety valve 1-3. As shown in the figure, Figure 11 The ignition assembly 12 includes a charge head 12-1 and a first leg wire 12-2 and a second leg wire 12-3 branched from the charge head 12-1. As shown in the figure, Figure 1 The first leg wire 12-2 is connected with the first connecting post 1-3-1, and the second leg wire 12-3 is connected with the second connecting post 1-3-2. The liquid injection valve 1-3-3 is communicated with the cavity of the visible module 1.

[0055] The charging pipe 2 is made of high-temperature-resistant transparent quartz material. As shown in the figure, Figure 10 The charging pipe 2 is provided with a plurality of mark groups 2-1 on the side facing the observation window 1-6. As shown in the figure, Figure 1 After the charging pipe 2 is mounted on the clamping seat 1-1-12, the head 12-1 of the ignition assembly 12 extends into the upper end of the charging pipe 2. The mark groups 2-1 are directed towards the observation window 1-6, which is beneficial to observing the combustion position.

[0056] As shown in the figure, Figure 1 、 Figure 2 The constant pressure valve 3 is connected with the control power supply 7 through the power supply line 8. The pressure gauge 6 is connected with the control power supply 7 through the signal line 10. The pressure sensor 11, the pressure gauge 6, the constant pressure valve 3 and the air release valve 5 are electrically connected.

[0057] The liquid carbon dioxide in the visual module 1 is filled to a certain set value, and after the ignition assembly 12 is ignited and powered, the medicine is ignited instantaneously, heat is transferred to the liquid carbon dioxide in the visual module 1, the pressure of the carbon dioxide rises, and the pressure in the visual module 1 also rises instantaneously. Within a few milliseconds, the constant pressure valve 3 opens the gas release valve 5 to release gas, so that the pressure in the visual module 1 is maintained at a set value. When the initial pressure in the visual module 1 is set to be relatively high, the burning speed of the medicine is extremely fast, and the pressure rising speed in the visual module 1 may be greater than the gas release rate of the constant pressure valve 3. When the pressure is higher than the predetermined value of the safety valve 3, the safety valve 1-3 is broken from the cross-shaped notch 1-3-4, and the high-pressure gas is released, so that the visual module 1 will not be damaged, and the safety of the test is ensured.

[0058] The test method of the test device for testing the burning speed of the excitation medicine of the carbon dioxide fracturing device under high pressure adopts the above-mentioned test device, and comprises the following steps:

[0059] 1) The first terminal post 1-3-1 and the second terminal post 1-3-2 of the safety valve 1-3 and the side facing the cavity are respectively connected with the first foot line 12-2 and the second foot line 12-3.

[0060] 2) Place the pipe body 1-1-1 on the horizontal ground, place the first sealing ring 1-2 in the installation ring groove 1-1-11, then install the safety valve 1-3 at the pipe opening, and then place the pressure ring 1-4 into the pipe opening, the pressure ring 1-4 is screwed with the pipe opening, the pressure ring 1-4 is screwed to extrude the first sealing ring 1-2 to maintain the sealing property of the upper part of the visual module 1.

[0061] 3) Fill the excitation medicine in the charging pipe 2 according to the fixed density; extend the charging pipe 2 from the window into the clamping hole of the clamping seat 1-1-12 and fix the charging pipe 2 in a straight state.

[0062] 4) Place the second sealing ring 1-5 on the installation groove 1-1-5 of the window, and then place the observation window 1-6, the observation window 1-6 is attached to the second sealing ring 1-5 to prevent the metal high-pressure-resistant sapphire observation window 1-6 from being damaged by directly attaching to the pipe body 1-1. Then place the gland 1-8 on the observation window 1-6, and then fix it through the fastener 1-7.

[0063] 5) Install the pressure sensor 11 on the fourth interface 1-1-9 and complete the debugging.

[0064] 6) Install the constant pressure valve 3 on the first interface 1-1-2, install the pressure gauge 6 on the second interface 1-1-7, and install the gas release valve 5 on the third interface 1-1-8.

[0065] 7) Connect signal line 10 between pressure gauge 6 and control power supply 7, and connect power supply line 8 between control power supply 7 and constant pressure valve 3. Set the pressure starting value of control power supply 7 as pressure value A (in this embodiment, A = 1 MPa).

[0066] 8) Fill liquid carbon dioxide into visual module 1 through injection valve 1-3-3 to make the internal pressure reach 1 MPa.

[0067] 9) Set up the camera and aim at the position of charge tube 2 of observation window 1-6, and turn on the camera to complete the debugging.

[0068] 10) Power on first terminal 1-3-1 and second terminal 1-3-2, ignite ignition assembly 12, and the charge head 12-1 ignites and excites the charge in charge tube 2, and the excited charge instantaneously transfers heat to the liquid carbon dioxide, so that the pressure in visual module 1 instantaneously rises to and exceeds 1 MPa. At this time, pressure gauge 6 obtains the internal pressure of pipe body 1-1-1, and transmits the signal to control power supply 7 through signal line 10, and control power supply 7 controls constant pressure valve 3 to instantaneously open the gas exhaust through power supply line 8, and constant pressure valve 3 starts to work to keep the pressure in visual module 1 within the preset value range;

[0069] 11) Calculation and analysis: when the excited charge is ignited by ignition assembly 12 and burns, the burning surface in charge tube 2 transfers from top to bottom, and sequentially passes through a plurality of mark groups 2-1 to form time parameters. For example, the number of mark groups 2-1 is 5, the interval between every two is a, and the five mark groups 2-1 form time t1, t2, t3, t4, t5 from top to bottom; set the time before starting the exhaust valve 5 as t, which is the time when the pressure in visual module 1 is kept at the preset value by constant pressure valve 3; compare t1-tm with t respectively, and select the value greater than t (for example, t3, t4, t5 are obtained; then t3, t4, t5 are the times when the burning surface of the charge passes through the high-speed camera mark point in turn after the pressure in visual module 1 is stabilized at the set value). Then divide a by the selected greater than t3, t4, t5 respectively to obtain the burning rate v3, v4, v5 of the excited charge, and take the average value v, which is the burning rate of the excited charge under the pressure A.

[0070] 12) Open exhaust valve 5 to empty the gas in visual module 1, and take out and replace charge tube 2.

[0071] 13) Set the pressure value B of the liquid carbon dioxide in visual module 1 (in this embodiment, B = 5 MPa).

[0072] Repeat steps 8) to 12) to output the burning rate of the excited charge under the preset pressure value B;

[0073] Repeat steps 7) - step 12) until the ignition propellant burning rate test under 10 mpa, 15 mpa, 20 mpa, 25 mpa, 30 mpa working conditions.

[0074] 14) The obtained 7 working conditions of pressure and corresponding burning rate v are fitted to obtain the relationship between the burning rate of the ignition propellant for the carbon dioxide fracturing device and the confining pressure.

[0075] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A testing device for the burning rate of the ignition agent in a high-pressure carbon dioxide fracturing device, comprising a high-pressure resistant visual module, characterized in that, It also includes a constant pressure valve, pressure gauge, ignition assembly, and high-temperature resistant transparent quartz propellant tube; The high-pressure resistant visual module has a cavity for storing liquid carbon dioxide. The bottom of the module has a base, and the top has a port communicating with the cavity. A rupture disc safety valve is installed at the port, and a pressure ring is placed on top of the valve. An observation window is provided on the axial wall of the module. The propellant tube is installed within the cavity, and multiple marking groups are provided on the side of the propellant tube facing the observation window. The ignition assembly connects the rupture disc safety valve and the high-temperature resistant transparent quartz propellant tube. The rupture disc safety valve has an injection valve for injecting liquid carbon dioxide into the cavity. The constant pressure valve and pressure gauge are both mounted on the visual module and communicate with the cavity. The constant pressure valve and pressure gauge are electrically connected. The top of the rupture disc safety valve has a cross-shaped groove that can rupture when the pressure is too high. The visual module also includes a container, a first sealing ring, a second sealing ring, and a pressure cap. The container includes a tube body, with the base at the bottom and the opening at the top. The cavity is located inside the tube body. The tube body has a window for installing an observation window, and the second sealing ring is installed between the observation window and the window. The observation window is fixed to the window by the pressure cap; the tube body is provided with an installation ring groove for installing the first sealing ring, and the rupture disc safety valve is set on the first sealing ring; a card seat is provided on the inner bottom surface of the tube body, and the card seat is provided with a card hole adapted to the high temperature resistant transparent quartz charge tube. The high temperature resistant transparent quartz charge tube is fixed to the card seat by a shaft hole snap-fit; the card seat protrudes upward by one end to form an effective fixed wall surface for installing the high temperature resistant transparent quartz charge tube, ensuring that the high temperature resistant transparent quartz charge tube is in a straight state.

2. The testing device for the burning rate of the ignition agent in a high-pressure carbon dioxide fracturing device according to claim 1, characterized in that, The window is recessed to form a mounting platform, and the observation window is placed on the mounting platform in an embedded manner.

3. The testing device for the burning rate of the ignition agent in a high-pressure carbon dioxide fracturing device according to claim 2, characterized in that, An installation groove is formed by sinking further inward from the mounting platform, and the second sealing ring is placed on the installation groove.

4. The testing device for the burning rate of the ignition agent in a high-pressure carbon dioxide fracturing device according to claim 1, characterized in that, It also includes a vent valve, which is installed on the high-pressure resistant visual module and communicates with the interior of the cavity.

5. The testing device for the burning rate of the ignition agent in a high-pressure carbon dioxide fracturing device according to claim 1, characterized in that, The intervals between multiple marker groups form time values.

6. A method for testing the burning rate of the ignition agent in a high-pressure carbon dioxide fracturing device using the testing apparatus as described in any one of claims 1-5, characterized in that, include: 1) Set the pressure value A of the liquid carbon dioxide in the high-pressure resistant visual module to the constant pressure valve; 2) Inject liquid carbon dioxide into the high-pressure resistant visual module through the injection valve to bring its internal pressure to the set value; 3) Set up the camera and aim it at the medicine tube at the observation window, then turn on the camera to complete the debugging; 4) Ignite the ignition assembly. The ignition assembly ignites and activates the agent in the charging tube. The activated agent instantly transfers heat to the liquid carbon dioxide. The pressure in the high-pressure resistant visual module instantly rises above the set value. The constant pressure valve starts to work to keep the pressure in the high-pressure resistant visual module within the set value range. 5) Calculation and analysis: When the igniting agent is ignited by the ignition component and starts to burn, the combustion surface in the charging tube is transmitted from top to bottom, and passes through multiple marker groups in sequence to form time parameters. Based on the time parameters, the burning rate of the igniting agent at the preset pressure value A is output. 6) Open the vent valve to release the gas inside the visual module, then remove and replace the loading tube; 7) Set the pressure value B of the liquid carbon dioxide in the visual module; Repeat steps 2)-6) to output the burning rate of the ignition agent at the preset pressure value B; Repeat steps 1)-6) until n preset pressure values ​​of the ignition agent combustion rate test are output; 8) Fit the obtained pressure and corresponding burning rate under n operating conditions to obtain the relationship between the burning rate of the initiating agent for the carbon dioxide fracturing device and the confining pressure.

7. The method according to claim 6, characterized in that, In step 5), the spacing between each pair of multiple marker groups is set to a, and the multiple marker groups are formed sequentially from top to bottom for time t1-tm; the time for the constant pressure valve to maintain the pressure in the visual module at the set value and before opening to release gas is set to t; the values ​​of t1-tm and t are compared respectively, and a value greater than t is selected; then a is divided by the selected value greater than t, thereby obtaining the combustion rate of the activating agent.

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